According to the Finnish Supreme Administrative court decision, Finland tax authority must pay interest on refunds of withholding tax collected in contrast to the EU law.
The interest rate imposed on withholding tax refunds varies annually. In the years 2006 to 2013, the interest rates ranged between 0.5% and 2.5%.
As the Supreme Administrative Court only issued the decision in September 2013, the Finnish tax administration has not yet issued guidelines as to how interest is to be calculated.